Wow, this is interesting. Personally my stutter only occurs when the thought becomes a word, or tries to. But in the past my stuttering has carried over into my piano practice. Sometimes when I would start to play a melody, I would play the first note more than once in a row for no reason, then stop myself and think "what the heck am I doing??" It really is annoying and I know how it feels. But my thoughts? I never think words, I just think subtle concepts and try to describe them without thinking how, i guess. Idk, but that sucks. Good luck brother, you'll get through it.